Fix sample rate issues - Githubissues

This PR addresses issue #152.

Changelog

MicrophoneAudioSource now detects supported sample rates and chooses the lowest possible one (higher than 16khz)
MicrophoneAudioSource no longer receives a sample_rate argument
Change block_size argument to block_duration in all audio sources
Fix bug in StreamingInference when resampling audio to pipeline's sample rate
Resample can now run on GPU by passing a device argument